Sharma R, Timiras P S
Mech Ageing Dev. 1986;37(3):249-56. doi: 10.1016/0047-6374(86)90042-4.
Specific binding of [3H]dexamethasone to cytosol and translocation of bound receptor complexes to purified nuclei were studied in the skeletal muscle of immature (3-week) and mature (26-week) Long-Evans male rats. A marked decrease (57%) in the specific binding sites with no apparent change in dissociation constant (Kd) was observed in the skeletal muscle of mature rats compared to immature. Heat activation (25 degrees C for 45 min) significantly enhances the nuclear binding of steroid-receptor complexes in the skeletal muscle of rats of both the ages at almost similar level. Cross-mixing experiments (i.e. binding of activated cytosol from mature rats to nuclei of immature and vice-versa) gave similar values. Interestingly, Ca2+-activated (0 degree C for 45 min with 20 mM Ca2+) nuclear translocation was significantly higher (27%) in the skeletal muscle of immature rats compared to mature. Our results indicate that glucocorticoid receptor level and some physicochemical properties change with age in the skeletal muscle of rats.
在未成熟（3周龄）和成熟（26周龄）的Long-Evans雄性大鼠的骨骼肌中，研究了[3H]地塞米松与胞质溶胶的特异性结合以及结合的受体复合物向纯化细胞核的转位。与未成熟大鼠相比，成熟大鼠骨骼肌中的特异性结合位点显著减少（57%），解离常数（Kd）无明显变化。热激活（25℃ 45分钟）可显著增强两个年龄组大鼠骨骼肌中类固醇受体复合物的核结合，且增强水平几乎相似。交叉混合实验（即将成熟大鼠的活化胞质溶胶与未成熟大鼠的细胞核结合，反之亦然）得到了相似的值。有趣的是，与成熟大鼠相比，未成熟大鼠骨骼肌中Ca2+激活（0℃ 45分钟，含20 mM Ca2+）的核转位显著更高（27%）。我们的结果表明，大鼠骨骼肌中糖皮质激素受体水平和一些物理化学性质会随年龄变化。
